Since the first release, Android has required developers to sign their applications. When you update an app, Android will compare the update's signature to the existing version. If they match, the app update will install. This way, developers don't have to worry about modified APKs causing problems, and users are kept secure.

If you were ever wondering what bootloader encryption, signing, and locking actually meant, this post is for you.

My name is Ivo, and recently I posted this write-up on Reddit (check out the Android subreddit while you’re there!). The post gained quite a bit of traction, and to spread the word further, I'm now posting it here at Android Police. I hope it helps out those of you who are confused.

It’s necessary, if you want to talk about these issues, to get some cryptic terms out of the way, so we actually know what we’re talking about! If you want to find out more about these topics, just click on through to their respective Wikipedia articles.